The present invention relates to a cell adhesive material applicable to cell culture containers or various medicinal materials and also relates to a method for producing the same. More specifically, the present invention relates particularly to a material with improved cell adhesion and a method for improving the adhesion.
For organs such as skin, mucosa, blood vessel, liver, and spleen which functions cannot be replaced satisfactorily with artificial materials alone, the trend to develop hybrid artificial organs of integrated cell type have been more popular in recent years. In such case, an important issue resides in the selection and designing of a matrix material on which culturing cells spread. For example, it is well known that the adhesion, growth and proliferation of endothelial cells depends on the state of fixing the cells. Matrices are generally constituted of polymer materials, and such polymer materials have conventionally been surface modified by a variety of processes.
Surface modification processes are schematically grouped in dry process representatively illustrated by plasma process, arc process, etc. and wet process represented by coating, graft polymerization, etc.
The plasma process includes, for example, non-reactive plasma process based on the sputtering action of inactive ions such as argon, etc., reactive plasma process using reactive gases such as oxygen, water vapor, etc. In any of these processes, the incident energy of ions is approximately several keV, which can modify cell adhesion or the contact angle of cells to water by rendering the surface of a polymer material in a rough surface or can give hydrophilicity via the introduction of polarized structures such as &gt;C.dbd.O group, C--O-- bond, and the like.
The coating is conducted by precoating an adhesive protein in solution from connective tissues such as collagen, fibronectin, etc. onto a matrix surface, thereby improving the adhesion of endothelial cells, fibroblasts, etc.
However, such conventional techniques still have some problems to be solved.
Firstly, the surface of polymer materials gets rough once the plasma process is effected, so the resulting surface is likely to suppress cell proliferation although it generally propagates cell adhesion. The plasma status varies depending on the apparatus, so uniform conditions for such process are substantially impossible to realize, resulting in no chance of improving controllability and reproducibility.
Alternatively, the coating has a problem in that the adhesive strength between a matrix and a cell is relatively weak because cells bond through the layer of an adhesive protein to the matrix.